东南景天对镉-苯并[a]芘复合污染土壤的修复效果

Remediation efficiency of Cd-B[a]P combined polluted soil by Sedum alfredii

采用盆栽试验研究2种生态型东南景天对镉-苯并[a]芘(Cd-B[a]P)复合污染土壤的修复效果.结果表明:在Cd-B[a]P复合处理条件下,超积累生态型东南景天生长主要受高浓度B[a]P影响,而Cd是抑制非积累生态型东南景天生长的主要因素,在低Cd处理条件下,5 mg·kg-1B[a]P能促进2种生态型东南景天根系的生长;超积累生态型东南景天地上部镉含量远远大于非积累生态型,且不受B[a]P水平的影响;2种生态型东南景天各部位B[a]P含量主要受土壤B[a]P水平的影响;在Cd-B[a]P复合处理条件下,超积累生态型东南景天对镉的去除效果显著高于非积累生态型,但在高质量浓度B[a]P(25 mg·kg-1)处理条件下,镉的去处效果明显降低;未种植物的土壤B[a]P平均去除率达到43.7%,而种植东南景天的土壤B[a]P平均去除率达到58.2%.本结果说明超积累生态型东南景天对中轻度Cd-B[a]P复合污染土壤具有较好的修复效果.

Remediation efficiency of cadmium（Cd） and benzo [a] pyrene（B[a]P） combined polluted soil by Sedum alfredii Hance was studied using pot experiment under controlled temperature and natural light during cultivation.The results showed that the growth of hyperaccumulating ecotype（HE） of S.alfredii was inhibited under high B[a]P level（25 mg·kg-1）,whereas the biomass of non-hyperaccumulating ecotype（NHE） decreased significantly due to Cd toxicity.When treated with low Cd（1 mg·kg-1）,the root biomass of both HE and NHE were increased by 5 mg·kg-1 B[a]P.Cadmium concentration in the shoot of the HE was much greater than the NHE and was not influenced by B[a]P supply level.The B[a]P concentrations in both shoot and root of both ecotype of S.alfredii were controlled by B[a]P level in the soil instead of Cd.The removal efficiency of Cd from Cd-B[a]P combined polluted soil by the HE was much greater than the NHE,however,significant decrease of Cd removal efficiency was observed with treatment of 25 mg·kg-1 B[a]P.The removal efficiency of B[a]P from unplanted soil was 43.7%,whereas it was increased to 58.2% after planted with both ecotypes of S.alfredii.All the results above suggest that hyperaccumulating ecotype of S.alfredii has great potential for phytoremediation of Cd and B[a]P moderately contaminated soil.